scholarly journals Two-dimensional mathematical model of autowave process in thin surface layer of liquid dispersed nanosystem (magnetic fluid)

2021 ◽  
Vol 2131 (2) ◽  
pp. 022012
Author(s):  
V Chekanov ◽  
A Kovalenko ◽  
E N Diskaeva ◽  
E Kirillova
Keyword(s):  
Mathematical Model ◽  
Magnetic Fluid ◽  
Process Modeling ◽  
Comsol Multiphysics ◽  
System Of Equations ◽  
Two Dimensional ◽  
Electrode Layer ◽  
Autowave Process ◽  
Comparison Of The Results ◽  
The Mathematical Model

Abstract In this work, a two-dimensional mathematical model of an autowave process taking place in a thin near-electrode layer of a magnetic fluid is constructed. The model is represented by a boundary value problem, which consists of a solution domain, a system of equations, initial and boundary conditions. The mathematical model is implemented in the COMSOL Multiphysics physical process modeling system. Comparison of the results of the numerical solution with experimental data prove the adequacy of the developed model.

MATHEMATICAL MODEL AND EXPERIMENTAL ESTIMATION OF THERMAL PROCESSES IN HEATING MODULE AS A PART OF STEAM ABLATION DEVICE FOR VARICOSE VEINS TREATMENT

2021 ◽  
pp. 117-125
Author(s):  
Дина Владимировна Кривоносова ◽  
Евгений Сергеевич Ермолаев
Keyword(s):  
Mathematical Model ◽  
Varicose Veins ◽  
Thermal Power ◽  
Thermal Characteristics ◽  
Steam Injection ◽  
Heating Element ◽  
Vein Wall ◽  
Tissue Heating ◽  
Comparison Of The Results ◽  
The Mathematical Model

На сегодняшний день в России для лечения варикозного расширения вен часто проводятся малоинвазивные операции методами радиочастотной или лазерной облитерации, при этом метод паровой облитерации при лечении варикозной болезни не применяется совсем. Однако метод паровой облитерации обладает существенными преимуществами: малый объём и биоинертность рабочей среды - водяного пара, его невысокая температура - 120 °С, исключающая вероятность образования нагара и перфорации венозной стенки. Целью данной работы является разработка математической модели для расчёта тепловых характеристик блока нагревания, входящего в устройство для лечения варикозной болезни методом паровой облитерации. Модель описывает теплообменные процессы в гидравлической трубке блока нагревания и может быть полезна при расчёте размеров нагревательного элемента, обеспечивающих нагрев и парообразование определённой порции воды. С целью верификации математической модели результаты моделирования были сопоставлены с экспериментальными данными. Была проведена серия экспериментов, в ходе которых были получены значения энергии, содержащейся в одной инжекции пара, и объём воды в одной инжекции, а также оценена фактическая тепловая мощность нагревателя. Сравнение результатов имитационного моделирования и значения фактической тепловой мощности пара, полученной экспериментальным путем, показала работоспособность математической модели. Разработанная математическая модель позволяет подбирать геометрические параметры нагревательного элемента в зависимости от требуемой тепловой мощности, которая должна быть обеспечена блоком нагревания, а также варьировать параметры нагревательного элемента для разной степени нагрева тканей Today in Russia minimally invasive varicose veins treatment is often performed using radiofrequency or laser ablation, while the method of steam ablation is not used at all. However, the steam ablation method has significant advantages: a small volume and biological inertness of the working substance - sterile water vapor, its low temperature - 120 °C, excluding the carbon deposits and perforation of the vein wall. The purpose of this work is to develop a mathematical model for calculating the thermal characteristics of the heating module as a part of the device for varicose veins treatment using steam ablation. The model describes heat exchange processes in the hydraulic circuit of the heating module and can be applied to calculate the dimensions of the heating module which provides heating and vaporization of a certain portion of water. In order to verify the mathematical model, the simulation results were compared with experimental data. A series of experiments were carried out in which the energy contained in one steam injection and the volume of water in one injection were estimated, as well as the actual thermal power of the heating module. Comparison of the results of simulation and the value of the actual thermal power of steam obtained experimentally showed the efficiency of the mathematical model. The proposed mathematical model allows to select the geometric parameters of the heating element depending on the required thermal power, which must be provided by the heating module, and also to vary the parameters of the heating element for different degrees of tissue heating

Numerical Simulation of Subsea Cluster Manifold Installation by the Sheave Method

2018 ◽  
Author(s):  
Yu Zhao ◽  
Yingying Wang ◽  
Liwei Li ◽  
Chao Yang ◽  
Yang Du ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
South China Sea ◽  
Deep Sea ◽  
High Reliability ◽  
Two Dimensional ◽  
Complex Environment ◽  
Lumped Mass ◽  
Lumped Mass Method ◽  
The Mathematical Model

The sheave installation method (SIM) is an effective and non-conventional method to solve the installation of subsea equipment in deep water (>1000m), which has been developed to deploy the 175t Roncador Manifold I into 1,885 meters water depth in 2002. With the weight increment of subsea cluster manifold, how to solve its installation with the high reliability in the deep sea is still a great challenge. In this paper, the installation of the 300t subsea cluster manifold using the SIM is studied in the two-dimensional coordinate system. The mathematical model is established and the lumped mass method is used to calculate the hydrodynamic forces of the wireropes. Taking into account the complex environment loads, the numerical simulation of the lowering process is carried out by OrcaFlex. The displacement and vibration of the subsea cluster manifold in the z-axis direction and the effective tension at the top of the wireropes can be gotten, which can provide guidance for the installation of the cluster manifold in the South China Sea.

scholarly journals Process modeling in sensor - object system when scanning underwater communications

2017 ◽  
pp. 84-94
Author(s):  
S. G. Cherny ◽  
A. A. Zhilenkov
Keyword(s):  
Mathematical Model ◽  
Process Modeling ◽  
Local Structure ◽  
Practical Importance ◽  
Underwater Vehicles ◽  
Water Area ◽  
Underwater Communication ◽  
Underwater Communications ◽  
Unmanned Underwater Vehicles ◽  
The Mathematical Model

The study focuses on the modeled processes describing the interaction of the scanning sensor with the element of underwater communication. This task is relevant in constructing the systems for automated monitoring of underwater objects by means of unmanned underwater vehicles. A simple model has been obtained that makes it possible to describe the structural properties of the object’s material or damage on its surface. The mathematical model of interaction between the object and the scanning sensor is presented as a sum of two series. The study shows that in problems of controlling the local structure of the object’s surface, it is possible to present the mathematical model in Kotelnikov expanded form. The obtained results are of high practical importance in solving the problems of laying specialized lines and highways in the territory of the Crimean water area of the Azov-Black Sea basin and regular monitoring their condition

Heat Convection from a Horizontal Cylinder Rotating in a Quiescent Fluid

1986 ◽  
Vol 10 (3) ◽  
pp. 141-152
Author(s):  
H.M. Badr ◽  
S.M. Ahmed
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Horizontal Cylinder ◽  
Heat Transfer Process ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Boussinesq Fluid ◽  
The Mathematical Model ◽  
Quiescent Fluid

The aim of this work is a theoretical investigation to the problem of heat transfer from an isothermal horizontal cylinder rotating in a quiescent fluid. The study is based on the solution of the conservation equations of mass, momentum and energy for two-dimensional flow of a Boussinesq fluid. The effects of the parameters which influence the heat transfer process namely the Reynolds number and Grashof number are considered while the Prandtl number is held constant. Streamline and isotherm patterns are obtained from the mathematical model and the results are compared with previous experimental data. A satisfactory agreement was found.

Valve Gear Refinement

2000 ◽  
Vol 124 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Jurij Avsec ◽  
Milan Marcic ◽  
Maks Oblak
Keyword(s):  
Mathematical Model ◽  
Cam Design ◽  
Cam Follower ◽  
New Type ◽  
Cam Profile ◽  
Profile Design ◽  
Comparison Of The Results ◽  
The Mathematical Model ◽  
Valve Gear ◽  
Lubrication Properties

This paper describes a new type of valve gear cam—MULTICAM—which consists of seven curves and allows an optimum cam profile design. In order to calculate the cinematic and dynamic values and to assess the minimum oil film thickness in the valve gear, the mathematical model of an ideal valve gear was used. In addition, the comparison of the results between the polysine cam and the new MULTICAM cam design was made. By means of the new cam design the Hertz pressures were reduced at the point of contact between the cam and the cam follower and the lubrication properties at the top of the cam improved.

scholarly journals MATHEMATICAL AND PHYSICAL BASIS FOR DEVELOPING A SIMULATOR FOR TOWING AND PULLING OF WHEELED AND TRACKED MACHINES

2021 ◽  
Vol 5 (4) ◽  
pp. 135-139
Author(s):  
Alexander Serhieiev ◽  
Andriy Krivoshapka ◽  
Oleksandr Isakov ◽  
Vyacheslav Lysenko ◽  
Viktor Moskalenko ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Physical Basis ◽  
Design Parameters ◽  
System Of Equations ◽  
Aramid Fibers ◽  
Tracked Vehicles ◽  
General Scientific ◽  
And Performance ◽  
The Mathematical Model ◽  
Physical Quantities

The subject matter of the article is the towing and pulling of wheeled and tracked vehicles with the use of cable ropes and dynamic slings. The goal of the study is to determine the mathematical and physical basis for the development of a simulator for towing and pulling wheeled and tracked vehicles for researching to study the possibility of using aramid fibers of cable-ropes and dynamic slings. The tasks to be solved are: based on the analysis of the main roads and ground characteristics to formalize the list of calculated parameters and physical quantities determine the amount of evacuation work when pulling, towing and transporting wheeled and tracked vehicles; to develop a mathematical model that describes the process of pulling and towing wheeled and tracked vehicles using cable ropes and dynamic slings. General scientific and special methods of scientific knowledge are used. The following results are obtained. By analyzing the main characteristics of roads and ground, a formalized list of design parameters and physical quantities that determine the volume of evacuation work during the towing and pulling of wheeled and tracked vehicles was obtained. Mathematical model, describes the process of pulling and towing wheeled and tracked machines using cable ropes and dynamic slings have been  compiled as a system of equations with different order. analyzed existing technology for the production of aramid fibers, their strengths and weaknesses, and formed a research polygon with regard to the peculiarities of the operation of wheeled and tracked vehicles. Existing technology for the production of aramid fibers, their strengths and weaknesses, and formed a research polygon with regard to the peculiarities of the operation of wheeled and tracked vehicles have been analyzed. Conclusions. The main roads and ground characteristics  that determine the vehicles. evacuation conditions are the following: the type of road or ground, their possibility depending on the season and precipitation, the presence of ascents and descents, as well as the nature of road (ground) interaction with caterpillars determined by resistance coefficients. movement and traction. The mathematical model of pulling a wheeled and tracked vehicle using cable ropes and dynamic can be presented as a system of equations: the jerk carried out by the machine in time reflected third-order differential equation, assuming that all the energy accumulated by the cable is numerically equal to the work of moving stuck machine, corresponds to the equality of the corresponding integrals; the properties of aramid fibers that affect the strength and performance characteristics of cable ropes can be formally expressed through the elongation of the cable. Analysis of strength and service properties of aramid fibers opens the way to improvement of manufacturing technology of cable ropes and dynamic slings for pulling and towing of wheeled and tracked vehicles.

scholarly journals The mathematical model of engagement and analytical description of tooth profile of waveform edge kinematic reducer

2021 ◽  
pp. 22-31
Author(s):  
M. A. Jasem ◽  
◽  
P. Y. Krauinsh ◽  
◽  
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Spherical Surface ◽  
Analytical Description ◽  
System Of Equations ◽  
Mathematical Experiment ◽  
Pair Mating ◽  
The Mathematical Model ◽  
Spherical Motion

The problem of creating a waveform edge kinematical reducer with multi-pair gearing brings to the fore a range of issues in the field of geometric-kinematic gearing theory, which are considered in this work. The synthesis of multi-pair gearing for a waveform edge kinematical reducer, which ensures the constancy of their transfer function, provides for: development of a mathematical model of gearing taking into account the peculiarities of the interaction of teeth during special-spherical motion; description of the profile of the teeth by a system of equations for a spherical surface and for a normal section of teeth for internal gearing; identification with the help of the MathCAD 2010 Professional program of a mathematical experiment and determination of the area of existence of 100 % multi-pair mating of teeth by comparing the shape of their profile with the nature of the analytical function of multi-pair engagement

Inverse Dynamic Analysis of Spatial Manipulators with Elastic Legs

1988 ◽  
Vol 12 (2) ◽  
pp. 63-69
Author(s):  
K.H. Low ◽  
R.N. Dubey
Keyword(s):  
Mathematical Model ◽  
Hybrid System ◽  
Perturbation Technique ◽  
Flexible Manipulator ◽  
System Of Equations ◽  
Joint Motion ◽  
Inverse Dynamic ◽  
Inverse Dynamic Analysis ◽  
Deflection Theory ◽  
The Mathematical Model

This work presents a general formulation of flexible manipulator systems. The associated mathematical model results in a hybrid system of equations involving both ordinary and partial differential equations. The perturbation technique and model analysis have been used for the solution. In addition to the lineal deflection theory, an unperturbed joint-motion assumption has then been employed in order to further simplify the mathematical model. Finally, an inverse dynamic problem is solved using the proposed methodology.

Warranty Costs Assessment for Automotive Applications

2012 ◽  
Vol 433-440 ◽  
pp. 6108-6115
Author(s):  
Zdenek Vintr ◽  
Michal Vintr
Keyword(s):  
Mathematical Model ◽  
Automotive Industry ◽  
Two Dimensional ◽  
Automotive Applications ◽  
Product Reliability ◽  
Warranty Period ◽  
Warranty Costs ◽  
The Mathematical Model ◽  
The Relationship

The article deals with current problems of warranty costs in automotive applications. The two-dimensional warranty widely used in automotive industry is presented. The relationship between warranty costs and product reliability is also presented. The article analyses problems with estimation of a number of failure occurrence over a warranty period and estimation of costs related to repair failures. The mathematical model enables to predict warranty costs for two-dimensional warranty is presented. The article also deals with problems of estimation of an instant of warranty period expiration and demonstrates its estimation on an example of a vehicle.

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